Mixing valves are used to control the mixing ratio of two or more fluids, such as hot and cold water, that flow into the mixing valve, so that the exiting fluid is a desired mixture of the incoming fluids. The mixing valve has a pair of inlets to which the hot and cold water supplies are attached. The desired amounts of hot water and cold water merge within the mixing valve to produce water of the desired temperature, which then exits the valve through an outlet. In Parker, U.S. Pat. No. 2,614,851, for example, mixing is controlled by a manually-actuable cam that engages each of the inlet valves.
Known mixing valves have a limited ability to prevent fluid backflow or crossover flow between the inlets. The present invention addresses this drawback.